Focus on equations with a precipitate.
Total Ionic Equations
 Write the equation (synthesis, decomposition,
etc.)
 check for reactants and products that are soluble or
insoluble.
 We usually assume the reaction is in water.
 Use a solubility table to tell us what compounds
dissolve in water.
 If the compound is soluble (does dissolve in
water), then the compound splits into its
component ions.
 If the compound is insoluble (does NOT dissolve
in water), then it remains as a compound in solid
form (precipitate)
Water dipole-partial charges
Hydrophilic compounds
 When a soluble compound in is water, the partial
polarity of water molecules interact with the charges
on ions to dissolve the compound.
 Compounds that are dissolved in water may be termed
hydrophilic.
Solubility Chart
Solubilities Not on the Table!
 Gases only slightly dissolve in water
 Strong acids and bases dissolve in water
 Hydrochloric, Hydrobromic, Hydroiodic, Nitric,
Sulfuric, Perchloric Acids
 Group I hydroxides (should be on your chart anyway)
 Water slightly dissolves in water! (H+ and OH-)
 There are other tables and rules that cover more
compounds than your table!
Total Ionic Equations
Molecular Equation:
K2CrO4 + Pb(NO3)2  PbCrO4 + 2KNO3
Soluble
Soluble
Insoluble
Total Ionic Equation:
2 K+ + CrO4 -2 + Pb+2 + 2 NO3- 
PbCrO4 (s) + 2 K+ + 2 NO3Net Ionic Equation:
Pb+2 + CrO4 -2  PbCrO4 (s)
Soluble
Solubility Rules
 Courtesy Prof. Kenneth W. Busch
1. Salts containing Group I elements are soluble (Li+, Na+, K+, Cs+, Rb+). Exceptions to this
rule are rare. Salts containing the ammonium ion (NH4+) are also soluble.
2. Salts containing nitrate ion (NO3-) are generally soluble.
3. Salts containing Cl -, Br -, I - are generally soluble. Important exceptions to this rule are
halide salts of Ag+, Pb2+, and (Hg2)2+. Thus, AgCl, PbBr2, and Hg2Cl2 are all insoluble.
4. Most silver salts are insoluble. AgNO3 and Ag(C2H3O2) are common soluble salts of silver;
virtually anything else is insoluble.
5. Most sulfate salts are soluble. Important exceptions to this rule include BaSO4, PbSO4,
Ag2SO4 and SrSO4 .
6. Most hydroxide salts are only slightly soluble. Hydroxide salts of Group I elements are
soluble. Hydroxide salts of Group II elements (Ca, Sr, and Ba) are slightly soluble.
Hydroxide salts of transition metals and Al3+ are insoluble. Thus, Fe(OH)3, Al(OH)3,
Co(OH)2 are not soluble.
7. Most sulfides of transition metals are highly insoluble. Thus, CdS, FeS, ZnS, Ag2S are all
insoluble. Arsenic, antimony, bismuth, and lead sulfides are also insoluble.
8. Carbonates are frequently insoluble. Group II carbonates (Ca, Sr, and Ba) are insoluble.
Some other insoluble carbonates include FeCO3 and PbCO3.
9. Chromates are frequently insoluble. Examples: PbCrO4, BaCrO4
10. Phosphates are frequently insoluble. Examples: Ca3(PO4)2, Ag3PO4
11. Fluorides are frequently insoluble. Examples: BaF2, MgF2 PbF2.
Short version Top rules supersede any lower rules.
 Group 1 is soluble.
 NH4+ is soluble.
 Nitrate, acetate, or chlorate is soluble.
 Cl-, Br -, and I- are soluble, but NOT Ag+, Pb2+, and
(Hg2)2+.
 Silver is NOT soluble unless covered by rules 1-4.
 Sulfates are soluble, but NOT Ba2+, Ca2+, Pb2+, Ag+,
Sr2+.
Net Ionic Equations
These are the same as total ionic equations,
but you should cancel out ions that
appear on BOTH sides of the equation
Total Ionic Equation:
2 K+ + CrO4 -2 + Pb+2 + 2 NO3- 
PbCrO4 (s) + 2 K+ + 2 NO3-
Net Ionic Equation:
CrO4 -2 + Pb+2  PbCrO4 (s)
Net Ionic Equations
Try this one! Write the molecular, total ionic, and
net ionic equations for this reaction: Silver nitrate
reacts with Lead (II) Chloride in hot water.
Molecular: 2AgNO3 + PbCl2  2AgCl(s) + Pb(NO3)2
Total Ionic:
2Ag+1 + 2NO3 1- + Pb+2 + 2Cl -1  2AgCl(s) + Pb+2 + 2(NO3 1- )
Net Ionic: 2Ag+1 + 2Cl -1 2AgCl(s)